Reading the popular media or governmental press releases alone might lead us to despair at the prospects for renewables - something that’s flavour of the month today can be an environmental pariah the next. So what is really happening? Should we be battening down the hatches or making hay?
Something often overlooked in the renewables discussion is the importance of a fabric first approach. Given that heat alone accounts for nearly half of all energy consumption in the UK – of which domestic heat represents around a third – and that up to 97% of our existing building stock will still be in use in 2050, reducing the demand for energy associated with buildings is paramount.
Various attempts to legislate for this in new build have come and gone recently – including Code for Sustainable Homes and Zero Carbon Homes – and current building regulations are driving down the energy footprint of new build.
Passivhaus has been a great success for self-build, and several landlords and developers are taking this up too. While there can be a premium on these properties (and some in the UK have been built to this standard for similar costs to typical social housing), the reduced running costs make this a clear winner for new build.
However, that doesn’t start to address the energy burden of our existing buildings. Deep retrofit is needed – and indeed energy efficiency measures are the most cost effective way to decarbonise our homes. Not forgetting that building fabric improvements usually have lifespans longer than generation equipment – even to match the expected lifespan of the building itself.
There’s another key advantage of a fabric first approach for renewables – reducing the total energy envelope of a site means that any generation systems installed can be downsized – reducing capital costs, running costs (including renewable feedstocks and O&M), and even auxiliary equipment like heat emitters, thermal and electric storage.
Decarbonising heat is a tough challenge. There are many ways to cut carbon from our heat supply – and green gas has been a key development of late. And there are many ways to generate biogas – including from Cumbrian cheese, processing food waste and green arisings in an anaerobic digester, or indeed animal slurries and human waste.
By using a material that would otherwise be handled as waste, we can reduce the carbon impact of our heat supply, and divert more waste from landfill or incineration. The neat thing about biogas is that we can burn it along with natural gas in our boilers and furnaces – direct injection into the gas grid also currently attracts Renewable Heat Incentive payments, further sweetening the deal.
However, there are concerns about using feedstock like these – and indeed energy crops or wood fuels – should uptake increase significantly, and there is competition for these resources. Reducing the overall demand for heat with a fabric first approach means that a greater proportion of the remaining heat demand can be met by renewable fuels like biogas.
Another option is to electrify heat: heat pumps are back in fashion. This is an established technology – being rolled out in wonderfully strategic local authority-led schemes in Manchester, and on a massive scale extracting, not gas, but renewable heat from the North Sea for homes in Glasgow.
One major challenge for electrifying heat is that our heat demand profile is so “peaky” – blasting our draughty old homes first thing in the morning and last thing at night with heat from electricity would present a huge headache for the National Grid, already struggling to balance decentralised generation with demand. Nevertheless, as more large scale and local renewables come online and the grid factor drops, this could be a low carbon solution to our high heat demand – and retrofitting insulation to these properties would reduce the height of the peak in heat demand and make electrified heat a more realisable proposition.
The impact of fabric first is less obvious for electricity than heat – building fabric focuses on conserving heat, which is usually delivered by fuelled sources. But once we have designed out heat demand, or drastically reduced it with retrofit, then we need to renew our focus on decarbonising power.
Our marine resource is arguably the most reliable source of clean, renewable energy. We know what time and what height our tides will reach years into the future, and tidal could supply 20 TWh of energy per year to the UK. In addition to capturing wind energy through aerial turbines, wave energy could feasibly supply around 70TWh per year in the UK – that’s 23% of our electricity. From ducks to dams, buoys to barrages, the potential for electricity from our waters is huge.
Marine energy is difficult though – high development and infrastructure costs, coupled with important environmental controls mean that many developers never make it beyond a pilot phase.
However recent developments in marine are promising. Power first flowed from Nova Innovation’s tidal turbines on Shetland in August 2016 and more capacity was added at Inverness on the mainland weeks later. We are poised to start realising the potential of marine from Welsh and Cornish waters – and as Canada seeks to learn from British expertise, we are exporting this valuable know-how around the world. The challenge is to get beyond the demonstration phase and get more project deployed – current EU funding is making this possible, and we are set to continue to capture the benefits of our island’s energy resource.
The role of local authorities and communities in fabric first renewable energy systems
While 2016 saw the last award from the Urban Community Energy Fund, its sister, the Rural Community Energy Fund, continues to thrive. This is a lifeline for communities engaging in energy projects – and is also catalysing others to consider energy as part of other local issues. The potent combination of devolution and community energy groups has seen ownership and investment in energy shifting from national policy to hyper-local – including being written into Neighbourhood Plans awarded by local authorities.
Power to the people is decarbonising energy as well as democratising it – and community energy groups frequently use their operating profits to address fuel poverty through education and funding retrofit and efficiency measures. Together, this is a potent combination.
Local authorities are also on the front foot with promoting both energy efficiency and renewable energy generation – usually funded from European Regional Development Fund monies. This is enabling SMEs and other eligible groups to access free energy audits and even grants which is helping businesses and communities actually realise their energy and carbon saving ambitions. There are more projects to come online from the last ERDF round – but given recent political developments, local authorities may have to be more creative to find budget to support schemes like this in future.
All this has added up to some impressive outcomes at the last count: solar out-supplied coal for UK electricity in 2016; and renewables supplied the whole energy demand for cities like Burlington, Vermont, and even the whole of Portugal. Nuclear and gas are being pipped at the post on cost by large scale solar and onshore wind. And public perception of renewables remains consistently high – figures from the Department for Business, Energy and Industrial Strategy say that 79% of people support renewables, only 33% support nuclear, and 17% fracking.
Energy efficiency is considered the “first renewable”. We need a fabric first approach to improve energy productivity – delivering more benefit with less input. Passivhaus is an excellent solution for new build, with deep retrofit for our existing stock, will reduce the total energy burden for buildings, driving down the scale of renewable generation system required, associated investment need, auxiliary systems, and grid balancing services. Then we can truly move towards self-sufficiency in energy – with our renewable heat and power sources delivering an ever greater proportion of our energy needs.
Disclaimer: The sole responsibility for any views expressed lies with the author(s). Any opinions shared do not necessarily represent the views of Saint-Gobain.